I Saw the Light
Sunday, November 21st, 2010I have changed my mind again on this matter of using the RPGIII style of calling external programs instead of subprocedures, modules, service programs and all that sort of stuff. I am beginning to “see the light” about updating my coding style.
I don’t know why, but just out of the blue I started to mess around with the service program concept. I must have 15 or 20 variations on date conversion routines: GTOJ for MMDDYY to Julian, ISOTODOW for inputting an ISO date (CCYYMMDD) and outputting the day of the week, and ISOTOVBG for inputting ISO and outputting a spelled-out date (in the format September 30, 2010) are just a few of them. Somehow I guess I felt that there was a natural grouping evident there that ought to be respected.
So anyway, I began exploring service programs a bit more. I think my main objection to modules was the fact that compilation would be a three-step process- compiling the two modules separately with CRTRPGMOD, then using CRTPGM to create the final program. I considered this to be an incredible nuisance. But I pressed on and put all my date modules into one service program. I then discovered that there was a way in the header specifications to use a “binding directory” to join the main program to modules. I found out how to put service programs into a binding directory, then reference the modules from there.
The final step was freeing myself from a misconception about the use of service programs. The article I was using for reference only referred to the use of CRTPGM. I found, though, that once the binding directory reference was inserted into the H spec, I could use CRTBNDRPG, just like I always do, so it could be a one-step compilation again. This was important beyond simple ease of use, because a number of other programs I had written, including my file/program cross-reference system, provided for recompilation of programs when requested. Before, the few programs that had external subprocedures always bombed on the CRTBNDRPG compile, and I could think of no easy way to create the proper CRTRPGMOD/CRTPGM combinations automatically. That is partly why I had retained the old CALL/PARM syntax, so I would not have to deal with that issue. Now, my problem has been solved.
So maybe there is hope for me yet.